How did people know when to wake up to go to work in the early industrial revolution?

by FreddieMercury03

I was wondering how a poor working man or woman knew at what time to show up to their shift, or more specifically when to wake up for said shift? I assume not everyone had the money for a clock, and have heard stories of people sending their children to wait in front of the factories in order to wake their parents up when the time was right. Is this true, if not how did they do it, considering loosing your job could be detrimental.

CptNoble

There are some answers in the FAQ.